I’ve got an A-4010S that I’m trying to get working. The tape slips between the capstan and pinch roller. The spec calls for 7 lbs of pressure but I can’t get more than 2.5 lbs without the pressure roller solenoid dropping out shortly after it pulls in.
I looked at the voltage waveform on the solenoid when I press play and it’s 80 volts for 250 msec and then suddenly drops to 32 volts. I don’t see any circuitry in the schematic to account for this.